Method and System for Touch-Free Control of Devices

ABSTRACT

The present invention provides a system and computerized method for receiving image information and translating it to computer inputs. In an embodiment of the invention, image information is received for a predetermined action space to identify an active body part. From such image information, depth information is extracted to interpret the actions of the active body part. Predetermined gestures can then be identified to provide input to a computer. For example, gestures that can be interpreted to mimic computerized touchscreen operation. Also, touchpad or mouse operations can be mimicked.

STATEMENT OF GOVERNMENT SPONSORED SUPPORT

This invention was made with Government support under contractN00014-07-1-0747-P00004 awarded by the Office of Naval Research. TheGovernment has certain rights in this invention.

FIELD OF THE INVENTION

The present invention generally relates to the field of image processingand user interfaces. More particularly, the present invention relates tointerpreting visual cues such as depth cues from image information.

BACKGROUND OF THE INVENTION

In many situations, the human experience is a three-dimensional onewhere body gestures play an important role. From an early age, childrenlearn to interpret three-dimensional gestures that become fullyengrained in an adult. Grabbing and moving actions are natural to ahuman.

To the extent that modern human experience requires much use ofcomputers, such computers are currently not designed to interpret thesenatural gestures. Instead, special input devices including mice,trackpads, and keyboards have been used, which do not lend themselves todirect and natural interaction with digital content.

Where other input devices have been developed to allow for the input ofnatural human gestures, an attached apparatus has been necessary. Forexample, grabbing and moving actions have required the use ofspecialized gloves or hand attachments that then requireless-than-natural movements to utilize.

The present invention is directed to, among other things, allowing auser to provide input to a computer using natural gestures without needfor an attached device. The present invention is also directed toproviding standard computer inputs without need for contact to inputdevices such as mice, touchpads, or keyboards.

SUMMARY OF THE INVENTION

The present invention provides a system and computerized method forreceiving image information and translating it to computer inputs. In anembodiment of the invention, image information is received for apredetermined action space to identify an active body part. From suchimage information, depth information is extracted to interpret theactions of the active body part. Predetermined gestures can then beidentified to provide input to a computer. For example, gestures thatcan be interpreted to mimic computerized touchscreen operation. Also,touchpad or mouse operations can be mimicked.

In other embodiments, gestures beyond standard computer inputs can beidentified. For example, grab and move hand gestures can be used toprovide input to a computer. Other gestures can also be identified bymaking use of the depth information from active parts.

In an embodiment, the active part can be an object such as sportingequipment, props, or other objects from which depth cue and movementoperation can be used to provide computer input. Such an embodiment canbe used in gaming applications.

These and other embodiments can be more fully appreciated upon anunderstanding of the detailed description of the invention as disclosedbelow in conjunction with the attached figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings will be used to more fully describe embodimentsof the present invention.

FIG. 1 is a block diagram of a computer system on which the presentinvention can be implemented.

FIG. 2 is an image of a portable computer and a depiction of variousactions spaces relative to the computer.

FIG. 3 is an image of a portable computer and a depiction of variousactions spaces relative to the computer.

FIG. 4 shows various perspectives of an image bending apparatusaccording to an embodiment of the invention.

FIG. 5 shows various states of an image bending apparatus according toan embodiment of the invention.

FIG. 6 shows a web cam that includes an mage bending apparatus accordingto an embodiment of the invention.

FIG. 7 shows a computer display and an action space according to anembodiment of the invention.

FIG. 8 shows hand gestures to initiate certain operations according toan embodiment of the invention.

FIG. 9 shows a hand gesture to initiate certain operations according toan embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Among other things, the present invention relates to methods,techniques, and algorithms that are intended to be implemented in adigital computer system 100 such as generally shown in FIG. 1. Such adigital computer is well-known in the art and may include the following.

Computer system 100 may include at least one central processing unit 102but may include many processors or processing cores. Computer system 100may further include memory 104 in different forms such as RAM, ROM, harddisk, optical drives, and removable drives that may further includedrive controllers and other hardware. Auxiliary storage 112 may also beinclude that can be similar to memory 104 but may be more remotelyincorporated such as in a distributed computer system with distributedmemory capabilities.

Computer system 100 may further include at least one output device 108such as a display unit, video hardware, or other peripherals (e.g.,printer). At least one input device 106 may also be included in computersystem 100 that may include a pointing device (e.g., mouse), a textinput device (e.g., keyboard), or touch screen.

Communications interfaces 114 also form an important aspect of computersystem 100 especially where computer system 100 is deployed as adistributed computer system. Computer interfaces 114 may include LANnetwork adapters, WAN network adapters, wireless interfaces, Bluetoothinterfaces, modems and other networking interfaces as currentlyavailable and as may be developed in the future.

Computer system 100 may further include other components 116 that may begenerally available components as well as specially developed componentsfor implementation of the present invention. Importantly, computersystem 100 incorporates various data buses 116 that are intended toallow for communication of the various components of computer system100. Data buses 116 include, for example, input/output buses and buscontrollers.

Indeed, the present invention is not limited to computer system 100 asknown at the time of the invention. Instead, the present invention isintended to be deployed in future computer systems with more advancedtechnology that can make use of all aspects of the present invention. Itis expected that computer technology will continue to advance but one ofordinary skill in the art will be able to take the present disclosureand implement the described teachings on the more advanced computers orother digital devices such as mobile telephones or “smart” televisionsas they become available. Moreover, the present invention may beimplemented on one or more distributed computers. Still further, thepresent invention may be implemented in various types of softwarelanguages including C, C++, and others. Also, one of ordinary skill inthe art is familiar with compiling software source code into executablesoftware that may be stored in various forms and in various media (e.g.,magnetic, optical, solid state, etc.). One of ordinary skill in the artis familiar with the use of computers and software languages and, withan understanding of the present disclosure, will be able to implementthe present teachings for use on a wide variety of computers.

The present disclosure provides a detailed explanation of the presentinvention with detailed explanations that allow one of ordinary skill inthe art to implement the present invention into a computerized method.Certain of these and other details are not included in the presentdisclosure so as not to detract from the teachings presented herein butit is understood that one of ordinary skill in the at would be familiarwith such details.

The present invention makes use of digitized image and video informationthat can be captured in various ways so as to extract depth cues. Forexample, specialized cameras can be implemented that are designed tocapture depth cues from body image information. Also, more generalcameras, including web cameras, stereo cameras, and time-of-flightdevices, can be used to capture body image information where suchinformation is then used to generate depth cues. Still other types ofcameras can be used to capture, for example, infrared image information.Still other image information can be captured using time-of-flightcameras that use specialized lasers to capture depth information forbody images such as from information about the size of body parts.

In one embodiment of the invention, a webcam is used for image inputinformation. Multiple frames of the webcam image information are used togenerate depth cues to be used according to the present invention. Awebcam provides several advantages including its low cost as well as itswide application in modern computers. For example, as shown in FIG. 2, awebcam 202 as may be preinstalled in a laptop computer 204 may be used.An issue with the use of a webcam on a portable computer 204 is that itsfield of view may be fixed based on the position of the display 206.

For example webcam 202 is generally positioned by the position ofdisplay 206 that is set for a desirable viewing angle by a user. Inproviding a desirable viewing angle for display 206, webcam 202 is alsogenerally positioned to capture certain actions performed by the user.For example, in such a position, webcam 202 is able to capture bodyposition information directly in front of display 206. This can beappropriate when it is desired to capture gesture and other informationfrom user 208 in an action space 214 in front of display webcam 202 at adistance of approximately several feet. If information from a differentaction space is desired to be captured, webcam 202 of computer 204 maynot be properly positioned. For example webcam 202 is not able tocapture information from action space 212 that is directly above thekeyboard 208 or in action space 210 that is directly in front of display206. One manner of addressing this issue is to use multiple camerasdirected at different actions spaces.

Another manner of addressing this issue according to an embodiment ofthe invention is to use a light bending apparatus 300 of FIG. 3 that ispositioned around or near webcam 202 so as to reflect images from theappropriate action space. For example, as shown in FIG. 3, reflectingapparatus 300 is positioned in front of webcam 202 so as to captureimage information from action space 302 that is directly above keyboard210 of computer 204. Where it may be desirable to capture imageinformation from another action space, e.g., action space 304 directlyin front of display 206, mirrored apparatus 300 can be repositioned tocapture such image information.

As shown in FIG. 3, light-bending apparatus 300 makes use of a mirror soas to redirect image information from action spaces of interest towebcam 202. In other embodiments, light-bending apparatus 300 can beimplemented using other methods of bending light such as through the useof prisms or fiber optic cables. These and other methods of bendinglight are known to those of skill in the art and their implementationdoes not deviate from the present invention.

Shown in FIG. 4 is a more detailed view of an implementation oflight-bending apparatus 400 as implemented with a mirror 402. As shown,light-bending apparatus 400 includes a base 404 that is configured to bemounted on or around webcam 406 on a computer body (not shown). Forexample, base 404 may be permanently glued to the computer body. Inanother embodiment, hook and loop fasteners are used to provide alight-bending apparatus. Reflecting apparatus 400 includes mirror 408that is connected to base 404 by hinge 410. Mirror 408 can, therefore,be positioned to capture image information from a desired action spacesuch as discussed above.

Another embodiment of the invention is shown in FIG. 5. As shown in FIG.5, light-bending apparatus 502 is similar to reflecting apparatus 400with some notable enhancements. As shown in FIG. 5, light-bendingapparatus 502 includes a base 504 that allows mirror 310 to be slid intomultiple positions. For example, as shown in FIG. 5, three states areavailable: open as shown in FIG. 5A, closed as shown in FIG. 5B, andreflect as shown in FIG. 5 C. More specifically, as shown in FIG. 5A anopen state is shown with mirror 504 positioned to the side of camera 504such that the reflecting qualities of mirror 504 is not used. As shownin FIG. 5B a closed state is shown with mirror 504 positioned in frontof camera 504 and in a down position such that mirror 504 preventscamera 504 from receiving image information. As shown in FIG. 5C areflect state is shown with mirror 504 positioned in front of camera 504so as to capture image information from an action space of interest asdiscussed above. For example, in a reflecting position, light-bendingapparatus 502 can reflect image information from an action spacedirectly above the keyboard.

In an embodiment, light-bending apparatus 502 provides positioninformation that can be used by methods of the present invention.Position information can be provided by, for example, switches orlatches that respond to the position of mirror 504.

In an embodiment of the invention, a stand-alone webcam 600 as shown inFIG. 6 is used that is mounted on a swivel base 604. Swivel base 604allows stand-alone webcam 600 to be position as desired so as to captureappropriate action space information. In yet another embodiment,stand-alone webcam 600 is further configured with reflecting apparatus608. In such an embodiment, stand-alone webcam 600 may or may not have aswivel base but because of the functionality of light-bending apparatus600, a broad field of view is available to capture action spaces ofinterest.

In still another embodiment of the invention, a specialized depth cameramay be used. Such a depth camera may be for example a time-of-flightcamera that uses at least one infrared laser to determine depth of fieldinformation. In another embodiment of the invention, a stereoscopiccamera may be used. Such a camera uses two cameras separated by apredetermined distance that are used to provide slightly different imageinput from which three-dimensional depth of field information can beobtained.

It should be noted that where the light-bending apparatus implements amirror, the captured image information is a mirror image. In anembodiment of the invention, mirror image information is transformed tocorrected-image information before other algorithms are implemented. Inanother embodiment of the invention, mirror image information is notconverted and algorithms of the present invention account for suchmirror image information.

According to the present invention, various other coordinatetransformations can be implemented. For example, an embodiment of theinvention can implement fixed positioning where an action space includesfixed mapping between a calibrated action space and inputs to thepresent invention. For example, where action space 210 above display 206of FIG. 2 is used, fixed areas of display 206 correspond topredetermined inputs to the system so as to mimic a touchscreen. For atouchscreen-like implementation, a direct transformation system can alsobe used that maps a Cartesian space in the real world to Cartesiandisplay coordinates. Indirect fixed transformations can also be used totranslate from a curved or spherical real world space to a fixedCartesian space. Adaptive versions of these algorithms that adapt tochanging user behavior are also possible.

In another embodiment of the invention, adaptive positioning isimplemented. In this embodiment, the present invention adapts to inputsand maps such inputs to a fixed input. For example, in mimicking akeyboard on a table top, the present invention receives image input forthe hands and fingers of a user's hand and maps their movement to akeyboard to provide input to the system. The present invention can adaptto other inputs including mouse-like or trackpad-like movements.

In another embodiment of the invention, relative positioning is usedsuch as implemented in mouse inputs that make use of, for example,forwarding of velocities or acceleration instead of fixed positions.

In various embodiments of the invention, different action spaces areused where an action space is generally a space where actions areexpected to occur. Actions of interest can include hand and fingergestures as well as movements of other body parts. The present inventionmakes use of image information from the action space of interest togenerate depth cues to interpret the actions of interest.

In an embodiment of the invention, the action space can include the areadirectly near a screen of a computer such as action space 210 of FIG. 2.In this embodiment, the user touches different areas of the computerscreen that are received by the image input device and translated asinput to the system of the present invention. In this way, the presentinvention provides functionality similar to functionality provided by atouch-sensitive screen, sometimes also called touch screen.

System 700 as shown in FIG. 7 is exemplary. As shown, a user may bepresented with an image 706 on computer display 704 to which a user willrespond. For example, as shown, image 706 is in the form of a numberkeypad 708. A user can then be prompted to, for example, touch thescreen so as to enter a telephone number or other numeric information.Although the user would respond by touching areas of image 706, thescreen 704 need not be touch-sensitive. The system of the presentinvention can collect image information from action space 702 so as torespond appropriately. For example, in an embodiment of the invention, afinger tip is an action body part to which the invention responds. Bycapturing image information from action space 702 that provides image706 with an opportunity to make appropriate movements. The user can thentouch the screen where the image 706 appears.

An image input device as discussed previously, in this case a camera,receives input information that detects the presence of an action bodypart that has been predetermined to be an input point and furtherdetects actions of the action body part corresponding to a pressing,selection, or activation action. System 700, therefore, translates theactions of the user's forefinger as a touchscreen operation and furtherdetermines a mapping that determines the desired action by the user, inthis case, selection of certain numbers on a keypad.

Many more possibilities are available through the use of the presentinvention. In fact, essentially all mouse input actions can be providedthe touchscreen mode of the present invention. For example, click anddrag operations are available where the system of the present inventiondetects a press down action of a user's finger on the virtualtouchscreen of FIG. 7 and then detects a dragging operation across thescreen. Notably, the present invention, detects these actions throughthe image input device and not necessarily input information from aconventional touchscreen with touch sensors (e.g., capacitive sensors)on the screen.

In another embodiment of the invention, the action space includeshovering over a computer display without need to actually touch thedisplay. In this embodiment, rather than a user touching the computerdisplay, the user instead hovers over the display and performsessentially the same actions of the virtual touchscreen embodimentexcept that it is not necessary to touch the display. This embodimentcan be desirable because it avoids blemishing the computer display withoils or soil that may be present on a user's hand. Also, this embodimentmay be desirable so as to avoid physical damage to a computer display.

In this embodiment, the system of the present invention translates anaction space 710 that is a predetermined distance above the computerdisplay into an action space.

In another embodiment of the invention, the action space of interest canbe action space 212 above keyboard 208 as shown in FIG. 2. From actionspace 212, the present invention makes use of information relating to auser's hands or fingers so as to generate input to a computer includingbut not limited to mouse-like inputs. In making use of action space 212,the space above keyboard 208 can be used but inputs from the keyboardcan also be used. For example, the present invention can make use of theposition of a user's forefinger and can further detect that theforefinger is making a downward motion. Such downward motion can also bedetected by keyboard 208 as the pressing of certain keys. The pressingof keys can also serve to calibrate the detected position of the user'sforefinger or other body part. In this embodiment, the movements andactions are similar to those used for a traditional touchpad where auser can move his forefinger in action space 212 for touchpad movementoperations and can further make up-and-down finger motions for clickingoperations. Many more operations, however, are possible.

In another embodiment of the invention, an action space can be a spaceover any other object including, for example, a table top. Touchpad-likeoperations as described above can be made without need for direct inputto a computer. In yet another embodiment of the invention, fingerpositions are detected in such an action space to mimic a keyboard. Insuch an embodiment, a user can make keyboard movements such as would beperformed on a QWERTY keyboard to provide input to a computer. Atemplate could be used with an outline of a keyboard but the presentinvention does not require such a template.

In another embodiment of the invention, action space 214 between theuser and the computer 204 of FIG. 2 is used. In this embodiment, auser's fingers, hands, head position, or other position information aredetected so as to provide a wide variety of input signals. Conventionalmouse input signals are available in this embodiment but so are manymore types of input signals. For example, with the general position of auser's hands available as input, common hand movements can beinterpreted as input. For example, hand and arm positions can bedetected to provide grabbing and moving actions. Such an embodiment canbe used in computerized game applications for example.

Along with body part detection, other objects can also be detected. Forexample, in gaming applications, sports equipment or props can bedetected, including tennis rackets, bats, mitts, balls, etc. Also, in awriting application, the position of a pen, for example, can be detectedas text or signature input.

Other hand information can also be made available including the back orpalm position of a user's hand. Also, the position of a user's primaryinput finger (e.g., forefinger) is available. Still further, theposition of each of a user's fingers can be tracked and used as input.

The input system of the present invention can be used as a replacementfor conventional input devices but can also be used in connection withand as a supplement to conventional input devices. For example, in anembodiment of the invention, key strokes, mouse movements, and clickscan be used to turn on features of the present invention. In anembodiment, a combination of keystrokes is used to initiate operation ofthe present invention. In another embodiment, menu selections and mouseclicks are used to initiate operation of the present invention.

In yet another embodiment of the present invention, the system isinitiated by performing predetermined actions. For example, the systemof the present invention can be initiated as shown in FIG. 8 when a usertouches his thumb 802L to his forefinger 804L while simultaneouslytouching his thumb 802R to his forefinger 804R. These finger motionsprovide an affirmative signal to the present invention that features ofthe present invention should be initiated. It is important to note thatin this embodiment of the invention, the system of the present inventionis operable before the user touches his fingers together, but the systemmay not be in full operation to provide predetermined inputs to thecomputer system (e.g., mouse clicks, drag and drop, etc.). The system isat least operable to detect the presence of the initiation signal (e.g.,touching thumbs and forefingers together).

FIG. 9 demonstrates another gesture that can be used to initiate thesystem of the present invention. As shown, a user's hand 902 performs aflicking operation by moving from a position 904 to a position 906 asindicated by arrow 908. In another embodiment of the invention, two-handflicking, hand swipes, or finger motions are used to initiate operationof the system. In an embodiment of the invention, gestures used toinitiate the system of the present invention are selected as generallyunusual gestures that are not common during the use of a computer systemso as not to inadvertently initiate the system.

In an embodiment of the invention, the system of the present inventionidentifies an active part of a user's body. For example, an active partcan be the user's forefinger 806 or the tip of the user's forefinger 808as shown in FIG. 8. In other embodiments of the present invention, anactive part can be more than one of a user's fingers, at least one ofuser's hand 902 as shown in FIG. 9, and can even include the arms,shoulders, and head, or eyes of a user.

In an embodiment of the invention where the position of a user'sforefinger 808 (FIG. 8) is the active part, it can be necessary toidentify the palm 910 (FIG. 9) and backside 912 (FIG. 9) of a user'shands. In this embodiment, the skin color of the hand is tracked and theshades of a user's palm and backside can be learned in a computerizedmethod.

In another embodiment of the invention, a background subtractionalgorithm is used to identify a user's hands. In this embodiment, abackground is identified that is known to be in the absence of a user'shands. Upon detection of a user's hands, the algorithm performs abackground subtraction to identify the changing position of a user'sarms, hands, and fingers. In another embodiment, a change detectionalgorithm is implemented to detect the presence of moving and stationaryobjects. From identified moving objects, the position of a user's arms,hands, and fingers can be determined.

In an embodiment of the invention, a primary active part is a user'sforefinger tip 808 (FIG. 8). Various algorithms are available fordetermination of a user's fingertip. For example, shape and appearancedescriptors can be used to identify the fingertip of interest. A slidingwindow detector or a voting-based identification algorithm can also beused.

In an embodiment of the present invention, it is necessary to trackactive parts of user's body or other objects. Depth cues from thetracked parts can then be used to interpret the actions in the actionspace of interest. Tracking can be achieved using several algorithms.For example, tracking can be performed using an optical flow algorithm.Using such an algorithm, the movement of an active part of a user, forexample, a fingertip, can be followed across an action space. In anotherembodiment of the invention, a multi-hypothesis algorithm is used totrack active parts of a user's body.

In still another embodiment of the invention, a model-based trackingalgorithm is implemented. In such an embodiment, a three- ortwo-dimensional model of active parts of a user's body, for example, aredeveloped in a depth image using the image input signal. An iterativeclosest point algorithm can also be used for this purpose.

In the present invention, it is necessary to identify an active part,for example, a fingertip, in an action space. Various algorithms areavailable for this purpose.

For example, an algorithm for color-based tracking under varyingillumination can be used for real-time skin segmentation in videosequences. The skin segments can include the skin of a fingertip,finger, hand, palm, arm, etc. This algorithm enables reliable skinsegmentation despite wide variation in illumination during tracking andlocalization.

In this algorithm, an explicit second order Markov model is used topredict evolution of the skin color histogram over time. Histograms aredynamically updated based on feedback from the current segmentation andbased on predictions of the Markov model. The evolution of the skincolor distribution at each frame is parameterized by translation,scaling and rotation in color space. Consequent changes in geometricparameterization of the distribution are propagated by warping andre-sampling the histogram. The parameters of the discrete-time dynamicMarkov model are estimated using Maximum Likelihood Estimation, and alsoevolve over time. Quantitative evaluation of the method has beenconducted on labeled ground-truth video sequences taken from popularmovies.

Multiple hypothesis tracking for multiple target tracking can also beused for active part localization. In this algorithm, the targettracking objective is to collect image data from a field of viewcontaining one or more potential targets of interest (e.g., active part)and to then partition the image data into sets of observations, ortracks that are produced by the same object (or target). The term targetis used in a general sense.

Once tracks are formed and confined (so that background and other falsetargets are reduced), the number of targets of interest can be estimatedand quantities such as target velocity, future predicted position, andtarget classification characteristics can be computed for each track. Inthis algorithm, multiple targets (e.g., multiple fingers, hands, bodyparts, etc.) can be tracked.

A template matching algorithm can also be used for active partlocalization. Template matching is find objects in an image (e.g.,fingers, hands, etc.) which match a template image. Template matchingcan be subdivided between two approaches: feature-based and globalmatching. The feature-based approach uses the features of the search andtemplate image, such as edges or corners, as the primary match-measuringmetrics to find the best matching location of the template in the sourceimage. The global approach, uses the entire template, with generally asum-comparing metric (e.g., cross-correlation) that determines the bestlocation by testing all or a sample of the viable test locations withinthe search image that the template image may match up to.

If the template image has strong features, a feature-based approach maybe considered; the approach may prove further useful if the match in thesearch image might be transformed in some fashion. Since this approachdoes not consider the entirety of the template image, it can be morecomputationally efficient when working with source images of largerresolution, as the alternative approach, template-based, may requiresearching potentially large amounts of points in order to determine thebest matching location.

For templates without strong features, or for when the bulk of thetemplate image constitutes the matching image, a template-based approachmay be effective. Template-based template matching can use a sampling ofa large number of points. It is possible to reduce the number ofsampling points by reducing the resolution of the search and templateimages by the same factor and performing the operation on the resultantdownsized images (multiresolution, or pyramid, image processing),providing a search window of data points within the search image so thatthe template does not have to search every viable data point, or acombination of both.

An Iterative Closest Point (ICP) algorithm can also be used thatminimize the difference between two clouds of points in an image. Suchan ICP algorithm can be used to reconstruct two-dimensional orthree-dimensional surfaces from different scans to localize active bodyparts. The algorithm iteratively revises the transformation(translation, rotation) needed to minimize the distance between thepoints of two raw scans.

It should be appreciated by those skilled in the art that the specificembodiments disclosed above may be readily utilized as a basis formodifying or designing other image processing algorithms or systems. Itshould also be appreciated by those skilled in the art that suchmodifications do not depart from the scope of the invention as set forthin the appended claims.

1. A method for providing input to a device, comprising: receivingmultiple image information for a first predetermined space; identifyingat least one active part from the image information; generating actioninformation for the at least one active part in the first predeterminedspace; identifying a predetermined gesture of the at least one activepart.
 2. The method of claim 1, wherein the action information includesdepth cue information.
 3. The method of claim 1, further includingperforming a predetermined operation responsive to the identifiedpredetermined gesture.
 4. The method of claim 1, wherein the method isperformed in real-time.
 5. The method of claim 1, wherein the firstpredetermined space is a space substantially near a display device. 6.The method of claim 1, wherein the first predetermined space is a spaceabove a keyboard.
 7. The method of claim 1, wherein the firstpredetermined space is a space between a user and a display device. 8.The method of claim 1, further comprising mapping the firstpredetermined space to a second predetermined space.
 9. The method ofclaim 8, wherein the second predetermined space corresponds to thedisplay device.
 10. The method of claim 1, wherein the active partincludes a hand.
 11. The method of claim 1, wherein the active partincludes a fingertip.
 12. The method of claim 1, wherein the active partincludes a prop.
 13. The method of claim 1, wherein a multiple gesturehypothesis is implemented
 14. The method of claim 1, wherein the atleast one active part includes multiple parts of a human body.
 15. Themethod of claim 1, wherein the at least one active part includes a upperbody part.
 16. The method of claim 1, wherein image information isreceived from a camera.
 17. The method of claim 16, wherein the camerareceives light from a light-bending apparatus.
 18. The method of claim1, wherein the predetermined gesture initiates further identification ofpredetermined gestures.
 19. The method of claim 1, wherein thepredetermined gesture is a finger movement.
 20. The method of claim 1,wherein the predetermined gesture is a hand movement.
 21. The method ofclaim 1, wherein the multiple image information is video information.22. A system for providing input to a device, comprising: a computersystem; a camera configured to receive image information frompredetermined part in a predetermined space; wherein the computer systemis configured to: receive multiple image information for a firstpredetermined space; identify at least one active part from the imageinformation; generate action information for the at least one activepart in the first predetermined space; identify a predetermined gestureof the at least one active part.
 23. The method of claim 22, wherein theaction information includes depth cue information.
 24. The system ofclaim 22, wherein the camera is a webcam.
 25. The system of claim 22,wherein the camera is a time-of-flight camera.
 26. The system of claim22, wherein the camera is a stereoscopic camera.
 27. The system of claim22, wherein the computer system is further configured to perform apredetermined operation responsive to the identified predeterminedgesture.
 28. The system of claim 22, wherein the first predeterminedspace is a space substantially near a display device.
 29. The system ofclaim 22, wherein the first predetermined space is a space above akeyboard.
 30. The system of claim 22, wherein the first predeterminedspace is a space between a user and a display device.
 31. The system ofclaim 22, wherein the active part includes a prop.
 32. The system ofclaim 22, wherein the at least one active part includes a human body.33. The system of claim 22, further including a light bending apparatusthat directs light to the camera.